John Prescott: 'What’s this bloody article about? You writing an encyclopaedia on social life?'
Photograph: David Levene for the Guardian

When I arrive at John Prescott's flat, he is at his desk, a telephone in one hand and a letter in the other. "Can't get the bugger to answer," he growls. He is trying, he explains, to call a man called O'Reilly, who has just written him an astonishingly rude letter on stationery illustrated with a drawing of a foxhunter.

"I always ring 'em up," the former deputy prime minister explains, as he goes to dial again. Is it a drag to have to respond to abusive correspondents, I ask, or does he enjoy it?

"Oh, I want to ring him!" Alas, the man fails to pick up the phone, so Prescott offers a vivid impression of what he would have said had O'Reilly answered. "I'd start off saying, 'Reilly! Prescott here. I've got your letter here.'" Prescott adopts a music hall caricature of a posh accent. "And it just proves how ignorant you foxhunting fraternity are! The language is terrible, and me as a former seaman, well, I'm not used to it. Obviously it's normal for you public-school boys. And I know you went to public school," he adds, triumphantly knowing. "Addressing me as 'Prescott' was the giveaway!"

Then he is off on to an anecdote about another rude letter-writer, a colonel whose snooty butler refused to put Prescott through when he called. Somehow the story collides into another one, this time about a prison riot in the 70s, when the governor was insulting to him, and the officers reported Prescott to the police for an out-of-date car tax disc. Now suddenly it is 2001, and we are in Rhyl, the scene of his famous election campaign punch. "And the sisters were wetting their bloody knickers, with Harriet Harman saying: 'Ooh, we can't have a macho in our ranks.' But it was a conspiracy between the foxhunters and Adam Boulton and Sky! Sky used that footage to try and get rid of me! That were Boulton: 'Press your red button if you think Prescott should be sacked.' I'd have pressed his red button," Prescott glowers, "if I'd got anywhere near him."

Grievances keep tumbling out of him, a great waterfall of gleeful indignation and affront. On and on it comes, this torrent of memory, until, without any warning, he shudders to a halt and peers across at me suspiciously, as if only just registering my presence.

"What paper," he demands, "are you on anyway?"

I last interviewed Prescott in 2008, only a year after he had stood down from government. At the time, I remember marvelling that this great man-mountain of ungovernable emotion could have been in Downing Street for more than a decade – and three years on it is not so much a marvel as a total mystery. He is quite unlike any other politician I have ever met, with a mind that zigzags about all over the place, defying any convention of logic or order; and very rarely does he respond to a question with a direct answer. It is impossible to tell if he has heard the question and deliberately chosen to ignore it, or whether his mind has heard something else altogether, but the effect is less like a conversation than the confusing experience of eavesdropping on a crossed telephone wire.

He says he talks so fast because of his trade union background. "My experience of life is you don't go slow, or some bugger at a strike meeting'll jump in when you're drawing for breath, so you've got to keep talking and breathing." He can be gloriously catty, impersonating former cabinet colleagues with silly voices and a scornful roll of the eyes; at one point he has a bitch about David Blunkett, then nods to my notepad and adds: "Put it in braille, so he can read it." A baffling mixture of canny and unworldly, loyal and anarchic, he is in one sense an open book – only, it's a book full of indecipherable squiggles, and the qualities that made him so indispensable in Downing Street are impossible to read.

Everyone always said his real role was to provide a reassuring link between New and old Labour. But it can't be as simple as that, for why would both Tony Blair and Gordon Brown have trusted him to be their marriage-broker through the long years of bitter rivalry? That Prescott was indispensable to the fragile balance of power is beyond dispute – and you don't get to perform that role unless you have remarkable interpersonal skills, emotional tact and political judgment. It's just that for the life of me I can't see any evidence of it.

But God, he's good fun. A while ago the Radio 4 continuity announcer Alice Arnold tweeted that Prescott, a seaman in his youth, should read the Shipping Forecast; he promptly tweeted back with "*clears throat* Humber. Wind north-east 4 or 5, occasionally 6," and now the joke has turned into a stunt for Comic Relief. On Saturday 19 March, he will read the Shipping Forecast for real on Radio 4, just after midnight, to raise money for eating disorder charities, obliquely referencing his own history of bulimia.

For someone so sensitive about personal slights, he is surprisingly willing to send himself up these days. Last year he performed a cameo role playing himself in the sitcom Gavin and Stacey, last month he argued with Jeremy Clarkson on Top Gear about his M4 bus lane, and he is currently featuring in a moneysupermarket.com advert, playing himself as an angry-looking boxer who gets knocked out by his own punchbag. There is a fine line between good humour and self-parody, and when the advert came out I did worry, but he says it had nothing to do with showing off. "No! No, I come to the Lords, and I've got a fucking part-time secretary! That's why I did the boxing advert. To get money for a secretary."

He launches into a furious rant about the iniquities of pay and expenses in the House of Lords. "They pay you £300 a day and if you're not working you claim £150. That's supposed to be for your accommodation and business expenses. But you've got to tick on at 2.30. Well, I go in there at seven or eight o'clock in the morning. I'm not paid until after 2.30. I suppose that's all right for the blokes from the City who turn up after work. But I'm there from seven in the morning! And I share an office now with four lords, and they don't give me a full-time secretary. That's why I did the advert; to get money to hire a secretary."

Did he have any misgivings about appearing in an advert? "I did, yeah. What would the public think? But, well, first of all I wasn't doing the Parkinson thing, where you're advertising a particular product. This was basically saying go on to a compare dotcom." Then he is back on to his rant about the Lords.

"Look, right, the MP gets a full wage throughout the year, he gets money for the secretary, he gets travel expenses, all them things. I get £150 a day, right? And no fucking secretary, right? Now I'm doing the same job! If I was a union official, I'd be bloody leading them out! Now, look, I don't mind doing a job, but pay me the same as what you pay others I'm working alongside. It drives me, in a way, into doing other work, which I've always been against and never done for 40 years. Look, for 40 years I've never had a second job, just simply done my job. And, shockingly, I've had one house and one car. According to the press, I've had about five bloody cars! But I've got to be politically effective otherwise I might as well just get out of the game."

Some people, I suggest, might wonder why he doesn't just relax and enjoy the Lords as a gentleman's club. At 72, couldn't he kick back a bit? He looks genuinely appalled.

"I can't. I can't. That might be all right for the blokes from the City. But I'm not that kind of politician."

Prescott is certainly keeping himself busy, representing the Council of Europe and campaigning on climate change, human rights and the ongoing phone-hacking scandal at News International. He is particularly proud of a recent charitable venture to kit out an Indian village with 100 solar lamps. He is also one of the loudest voices in Westminster currently objecting to the alternative vote (AV).

Is there any truth in the claim that AV will help to restore public trust and political accountability? "Absolute nonsense! And what's the other thing they say? 'It'll bring in hard-working MPs.' The buggers that say it are part-time themselves half the time! Cashing in on their expenses while telling us we need to reform? What a load of crap! Clegg can't even remember when he's at work!"

Opponents of AV appear to be increasingly persuaded that the way to defeat it is by making the vote a referendum on Nick Clegg, but Prescott is doubtful about this strategy. "People have an opinion about Clegg, we all know he won The X Factor we call the general election, right? But we found with The X Factor, like, with the what do you call them? The Dead Beats? No, the Jedwards. People kept voting for them even though they were rubbish!"

He does not really think the electorate would take the same perverse pleasure in supporting Clegg, does he? "Well, Clegg won The X Factor, didn't he? And now we're getting the fucking result!"

So if Clegg shouldn't be the main focus of the anti-AV campaign, what should its message be? "I think the clear message is coalition. It's coalition. It's whether you can trust a political system to produce something you want when you vote in an election. And coalitions are less likely to do that."

Prescott isn't exactly disloyal to his leader, but his support is decidedly lukewarm. I ask how he thinks Ed is doing. "Who?" he says. Ed Miliband, I remind him. Prescott sighs.

"Look, I think he's got a difficult job. I always said I disagreed with his campaign, 'cos he talks as if there was no record. I think he's now put his jacket on, though, thank Christ. All this business of no tie, no jacket, I think that's wrong." I ask if he thinks Labour would be doing better under Ed's brother David, but Prescott is off on another rant about a political TV show he recently appeared on, whose producers told him, "We don't do ties." "I do," he told them. "You look bloody scruffy."

He has spoken to the last Labour leader only once since Brown left office. "I talk to Tony more than Gordon. But then Tony keeps in contact. Gordon switches off. I'm not going to tell you what I think about that, 'cos you'll bloody well print it. But we hear more from his wife than him, don't we? What is it with this wifeocracy? All the wives! Cherie Blair. Even Cameron's wife. They're all running round the fashion shops giving their political views. It's a wifeocracy! They're not elected by anybody! I mean, bloody hell, you've only got to talk about the Speaker's wife, haven't you? They only get on 'cos of who they're married to! They might not like this, but that's what it basically is."

Blair, in his memoir, describes Prescott as something of a dinosaur when it comes to his attitude towards women, and Prescott cheerfully admits, "I've never changed a nappy in my life." But then, unexpectedly tenderly, he adds: "But I do realise that was a mistake. Seeing my son David with his daughter, I see I was wrong. I lost the enjoyment. I don't put my arms round my sons today, and I think I made a real mistake. The macho style. I made many mistakes about family life." When did he last tell his sons – both in their 40s – that he loved them? "I don't think ever. I don't think I ever have."

He says it is not true that his own marriage has been radically reformed since his affair with his diary secretary was exposed in 2006. People may think his wife Pauline is now in charge, but he says that's nonsense. "She's had her changes, though," he chuckles. "Now she insists on sitting in the back of the car," and he mimics a royal wave. And she does have a much higher public profile – inspired largely by her show-stealing appearance in a documentary he made in 2008 about social class.

"That programme was supposed to be all about class and it turned out to be all about my wife! They cut out the parts about bloody class!" His wife now, he laughs, receives invitations to functions addressed to "Pauline Prescott plus guest". He says he doesn't mind that at all; in fact, it makes him very proud. He fears he may have underestimated her intelligence for most of their married life, on account of her having been a housewife. Then, quite abruptly, he stops and glares. "What's this bloody article about? You writing an encyclopaedia on social life or something?"

Truthfully, by now I'm not entirely sure what it is about, for it is very hard to maintain any train of thought in the face of Prescott's thundering stream of consciousness. I'd planned to ask all about his campaign to get to the bottom of the tabloid phone-hacking scandal, but he unleashes a 20-minute tirade on the subject, by the end of which I have no idea what's going on. It is literally incomprehensible. But he sounds as if he is loving the battle, and a war against Murdoch, Fleet Street, and the Metropolitan police must be the perfect storm for Prescott.

"I do love it!" he exclaims happily. "I don't have to worry about what Gordon or Blair or whoever will think if I do this or that now." He jabs a finger into his chest. "I'm speaking for JP now." And off he strides to the House of Lords, for a meeting with officials, to shout at them about his lack of secretarial support.

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